Nickel dichloride triphenylphosphine

Dialkylindolines and 1,3-dialkylindoles are formed in poor yield (<10%) from the reaction of ethyl- or phenymagnesium bromide with 2-chloro-N-methyl-N-allylaniline in the presence of catalytic quantities of (bistriphenylphosphine)nickel dichloride.72 In a modification of this procedure, the allyl derivatives can be converted by stoichiometric amounts of tetrakis(triphenylphosphine)nickel into 1,3-dialkylindoles in moderate yield72 (Scheme 43) an initial process of oxidative addition and ensuing cyclization of arylnickel intermediates is thought to occur. In contrast to the nickel system,72 it has proved possible to achieve the indole synthesis by means of catalytic quantities of palladium acetate.73 It is preferable to use... 

A 500-ml reaction flask was charged with the step 1 product (43.1 mmol), the poly condensate of 4,4 -dichlorobenzophenone-2,2-bis(4-hydroxyphenyl)-1,1,1,3,3,3-hexa-fluoropropane (Mn 11,200 Da 1.80 mmol), bis(triphenylphosphine) nickel dichloride (1.35 mmol), sodium iodide (5.85 mmol), triphenylphosphine (18 mmol), and zinc (108 mmol). The mixture was dried under vacuum and then treated with 87 ml of N,N-dimethylacetamide and kept in the temperature range of 70-90°C. After 3 hours the mixture was diluted with 200 ml of V,V-dimethylacetamide and insoluble components removed by filtration. The filtrate was then added to 1.5 liters of methanol containing 10 vol% concentrated hydrochloric acid to precipitate the polymer. After collecting, the precipitate was dried to obtain 28.5 g of product having polyhydroxyl groups. 

The reaction of Grignard reagents with thiophene and benzo[6]thiophene in presence of bis(triphenylphosphine)nickel dichloride catalyst results in ring opening with replacement of C—S bonds by C—C bonds (Scheme 38) (79CC637). Thus phenylmagnesium bromide gives 1,4-diphenylbutadiene and phenylstilbene respectively as a 1 1 mixture of stereoisomers. 

Enol ethers react with phenyl- or methyl-magnesium bromide in the presence of bis(triphenylphosphine)nickel dichloride to give the corresponding phenyl-or methyl-substituted olefin in good yield (ca. 70%) [equation (17)]. The reaction fails with highly substituted enol ethers, with enolates, or with enamines. 

Coordination compounds of nickel <79AG(E)683> and cobalt <70BCJ3604> with trithiapen-talenes have been described. 2,5-Diphenyl-1,6,6aA4-trithiapentalene reacts with palladium dichloride, in the presence of triphenylphosphine, giving a coordination compound (15) in which a benzene ring is directly linked to palladium <79AG(E)684). 

Bis(triphenylphosphine)palladium dichloride [(Ph3P)2PdCl2] can also be used as a catalyst for the phase-transfer carbonylation of halides. However, considerably more drastic conditions [95°C, 5 atm] are required when compared with Co2(CO)8 (44). The carbonylation of allyl chlorides can be catalyzed by nickel tetracarbonyl, giving isomeric mixtures of bu-tenoic acids. There is evidence for the intermediacy of polynuclear nickel-ates in this phase-transfer process (45). Acetylene insertion did not occur... 

The unusual oxidant nickel peroxide converts aromatic aldehydes into carboxylic acids at 30-60 °C after 1.5-3 h in 58-100% yields [934. The oxidation of aldehydes to acids by pure ruthenium tetroxide results in very low yields [940. On the contrary, potassium ruthenate, prepared in situ from ruthenium trichloride and potassium persulfate in water and used in catalytic amounts, leads to a 99% yield of m-nitrobenzoic acid at room temperature after 2 h. Another oxidant, iodosobenzene in the presence of tris(triphenylphosphine)ruthenium dichloride, converts benzaldehyde into benzoic acid in 96% yield at room temperature [785]. The same reaction with a 91% yield is accomplished by treatment of benzaldehyde with osmium tetroxide as a catalyst and cumene hydroperoxide as a reoxidant [1163]. 

General Procedure for the Synthesis of -Amino Alkyl Propanoates 14 [19] To a stirred solution of aldehyde (9, 0.2 mmol) in toluene (2 mL) at room temperature, 2-methoxyaniline (11b, 0.2 mmol) was added. After 30 min, a solution of dimethylz-inc (0.4 mL, 2 M, 0.8 mmol) in toluene was added all at once. After 10 min, (15, 2R)-(V-methylephedrine (0.060 g, 0.33 mmol) was added, and the resulting solution was stirred at room temperature. After 60 min, the reaction was cooled down to -30 °C, alkyl bromoacetate (13,0.24 mmol) was added, followed immediately by tra-triphenylphosphine nickel(II)dichloride (10 mg, 0.015 mmol), stirred at the same temperature for 23-48 h, and then quenched by the addition of HCl 1 M (3 mL). The reaction was stirred for 3-10 min, and then the organic phase was separated, washed with saturated NaHC03 and brine, dried with Na2S04, and concentrated in vacuo to afford a crude product 14, which was purified by chromatography (cyclohexane/Et20, 8 2-95 5). 

Aldehydes can be oxidized by nickel [91] and ruthenium oxides. Whereas mthenium tetroxide [92] gives poor conversions to the corresponding acids, catalytic amounts of ruthenate [93] in the presence of a secondary oxidant, such as NaBrOs or K2S20g, give better yields. Other ruthenium species for the catalytic oxidation of aldehydes to carboxylic acids are tris(triphenylphosphine) ruthenium dichloride [94] in the presence of hypervalent iodine [95] and ruthenium trichloride [96] in combination with periodate [81]. 

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